79

The reason is simple: Chocolate contains cocoa which contains Theobromine. The darker the chocolate is (meaning the more cocoa it contains) the more theobromine it contains. This is a bitter alkaloid which is toxic to dogs (and also cats), but can be tolerated by humans. The reason for this is the much slower metabolization of theobromine in the animals (...


33

I’ll answer this theoretically, since that’s how it has been posed. And if we’re ignoring practicalities, we may as well posit that the substance in question will be introduced directly into the bloodstream (This is, of course, simple to do in reality, but not how most people consume their non-toxic substances.) The easiest way to show that any unspecified ...


29

1. Synopsis I'd like to preface this by saying don't randomly use medicines without a doctor's advice. It's fairly unlikely antivenom would cause you any harm but in some cases, antivenom could be dangerous and even lethal. You have to consider possible allergic reactions and the route of administration. In any case, it would be a stupid idea to blithely ...


26

Pigs and swine are so poisonous that you can hardly kill them with strychnine or other poisons. This is a non-sequitur. An animal being poisonous does not imply that it resists to poison, nor the reverse is true. In any case, to the extent of my knowledge pigs do not produce any specific poison. Obviously, if you could provide a more specific claim, this ...


25

The toxic ingredient in chocolate is in the mythylxanine class, a substance called theobromine. It is much like theophylline; overdoses of theophylline used to be very common before the advent of inhalers for the treatment of asthma. (Chocolate also has some caffeine in it, which may exacerbate the effects of theobromine.) As @Chris stated, it is only slowly ...


20

Yes. Taking antibiotics (and by extension antivirals and antineoplastics) at low doses is dangerous, as this creates an evolutionary pressure to evolve antibiotic resistance (or rather, incorporate through horizontal gene transfer). This is dangerous because an infection resulting from these bacteria will then be harder to treat. In the paper "Experimental ...


20

The confusion arises from the term weak, which has only to be interpreted in chemical terms. Weak acid, as you say, just means that the acid does not readily dissociate, not that its effects are weak! Just to say one, HF corrodes glass, something that not even smoking HCl does. Wikipedia has a nice summary of HF toxicity (see also the references in the ...


19

First, we need to understand that neurons have special proteins embedded in their membranes called ion channels. These allow dissolved ions such as sodium, potassium, and calcium to pass from one side of the membrane to the other. Neurons use these channels to control their electrical activity. Peptide neurotoxins such as the one produced by funnel spiders (...


18

The more "dangerous" properties of spicy peppers are chiefly due to capsaicin. Sigma-Aldrich sells purified capsaicin, for which they provide safety information, including an MSDS. Most of it is the usual, unsurprising set of warnings about irritation to eyes and the respiratory system. However, there are LD50 numbers: LD50 Oral - rat - male - 161.2 mg/...


16

Gasoline toxicity through ingestions seems to be a topic where there's not a great deal of in-depth information available. I don't know how this works for chronic use, as most literature refers to acute scenarios. Either way, orally ingested, 30-50g is said to be toxic to humans while 350g can be fatal.[3]. So... Gasoline's Constituents A lot of ...


16

First of all, great question! What you describe here is known as aposematism. Aposematism is the adapation of warning signals against the predator. This word is used for any sound, coloring, and odor used as a warning signal. Of course, for this question the focus is color. Honest indications Animal coloration is usually an honest indication of their ...


16

Nice question! I will directly begin with the process through which methamphetamine causes damage to neurons, putting in as much details as are known, and adding appropriate citations wherever required. Methamphetamine (METH) is known to act by increasing concentration of dopamine in brain1. When excess of dopamine is produced, it causes oxidative damage to ...


15

Short answer Many snake poisons target specific proteins not present in unicellular organisms. Background The question is admittedly broad but the idea behind this question is pretty much what you indicate in your post - many venoms target specific proteins and do not simply destroy their target by, e.g., disrupting gross cellular structure (like alcohol ...


15

General overview. Each toxin and poison probably have their own evolutionary "arms race". Generally, an organism contains a compound that is a bit harmful to other species. As a predator or prey species becomes tolerant to low doses of this compound through natural selection, the compound efficacy could be increased (again by natural selection) on a ...


14

I think its useful to say that nicotine is not very toxic to humans - cells don't die or get sick for typical smoking habits. Secondary health effects are possible, but here is a toxicological profiles. Nicotine is a toxin in large enough quantities and nicotine has an LD50 (lethal dose for 50% of individuals) of 0.5-1 mg Nicotine / kg of body weight. So ...


14

The situation is definitely an extremely complex one, and you should probably forget about having an exact equation to define it. When talking about the effects of a substance on the organism there are several factors to take into account. These are generally put together under the term pharmacodynamics. Some of the factor to take into account are: The ...


12

First of all: Yes, fluoride is toxic, but the toxicity depends largely on the form (soluble vs. unsoluble, which fluoride salt etc.) occurs. It also depends on the environment since insoluble salts which are subjected to strong acids can release fluorine ions. The certain toxic dose for adults is 32-64mg/kg body weight, a 75kg adult needs to take up between ...


11

It depends largely on the method of administration. If you are atomizing the substance and delivering it via water vapor, many, many substances have no known LDLo (lowest dose required to kill a member of the tested population). Almost any substance in existence has the potential to kill you if it is diluting your bloodstream via direct intravenous injection ...


10

There is a problem with definition of toxicity — things that are dangerous in large amounts aren't usually called toxic. In spite of this, you're right: everything can be dangerous to a human in large enough amounts, or if delivered improperly. For example, even water can be toxic if drank too much. Also, when it gets into the lungs, it may cause ...


9

Just to add an answer to the 'how does the body process gasoline?' portion of the question, the liver and kidney would be doing most of the work of removing the stuff from the system once it was absorbed in the digestive tract. The liver does most of the processing of toxins and their removal from the blood and would tend to do the most work in removing ...


9

This write up by Carl Zimmer basically covers anything I could have said. He links to a number of resources, in particular this pdf, which at a cursory glance looks utterly fascinating and very well done. Figure 1 in that pdf sums it all up, I guess, or to quote Carl: "Each lineage of venomous animals became deadly on its own, independent of all the ...


9

This is at best anecdotal evidence. First of all, urine is, although it has been thought otherwise for decades, not sterile. The bacteria in it just don't grow under the conditions used in the lab which are used to proof bladder infections. See these two articles: Evidence of uncultivated bacteria in the adult female bladder. Urine is not sterile: use of ...


9

This question asks about the urinary excretion of THC. Before answering the question I think you're getting at, I'll first note that cannabinoids (of which THC is one) are primarily metabolized by hepatic cytochromes rather than being excreted directly. This article is a classical pharmacokinetic paper on the topic if you’re able to access it; this one is a ...


9

Here is a link to the Public Health Statement for Aluminum produced by the Centers for Disease Control and Prevention (CDC) in the United States. There is much more information on the web page but the following are some of the more pertinent points to your question. Potential Health Effects Workers Workers who breathe large amounts of aluminum dusts ...


8

This is a bit of a news flash - the answer is probably yes. Reading through recent Nature articles this one popped up: Toxicology the learning curve. Where there are some intriguing examples of low concentration only toxic effects. It might be worth a read. The preface gives a review of the idea, going back to the 16th century physician Paracelcius ...


8

Nicotine acts as a ligand for nicotinic acetycholine receptors (nAChRs), which are ligand-gated ion channels normally activated by acetylcholine. This family of receptors is expressed in every mammalian cell (Schuller, 2009). A priori, at least to me, I'd suggest that it's a bad idea to chronically introduce a foreign substance that mimics the activity of an ...


8

The stinging hairs (trichomes) of the common North American nettle (Urtica dioica) are sharp, pointed cells. These nucleated cells are embedded in a base of smaller epidermal cells. The shaft of the trichome is composed of silica. Upon touch, the tip breaks off, leaving a sharp tip similar to a hypodermic needle. The hollow trichome penetrates the skin, and ...


8

Short answer The causes of death after heroin, cocain or cannabis overdose are mainly due to cardiac and respiratory arrest, and not to neurotoxic effects. Background The cause of death after a lethal overdose of your mentioned drugs are the following : Cocaine (lethal dose: 30 mg - 5 g via mucus membrane (EMCDDA)): Cocaine-related deaths are often a ...


8

Edible by whom? Lets assume humans. Yes all quadrpeds are edible though you may not want to eat every part. For example, the scent glands of a skunk, or the quills of a porcupine are repulsive or impossible to eat. Also, some organs, like the liver of a polar bear, which accumulates vitamin A to toxic (to humans) levels. It's impossible to say why this is ...


7

Clostridium botulinum toxin is present ubiquitously in soil. As such it is more than plausible that hay bails, which come into contact with soil can and I should expect almost probably will be infected with these bacteria. However it is not the mere presence of the bacteria itself which causes poisoning, it is the toxins they produce when the appropriate ...


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